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- /* Copyright (c) 2017, Google Inc.
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
- * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
- * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
- * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
-
- #include <openssl/ssl.h>
-
- #include <assert.h>
-
- #include <openssl/bytestring.h>
- #include <openssl/err.h>
-
- #include "internal.h"
- #include "../crypto/internal.h"
-
-
- namespace bssl {
-
- bool ssl_protocol_version_from_wire(uint16_t *out, uint16_t version) {
- switch (version) {
- case TLS1_VERSION:
- case TLS1_1_VERSION:
- case TLS1_2_VERSION:
- *out = version;
- return true;
-
- case TLS1_3_DRAFT23_VERSION:
- case TLS1_3_DRAFT28_VERSION:
- *out = TLS1_3_VERSION;
- return true;
-
- case DTLS1_VERSION:
- // DTLS 1.0 is analogous to TLS 1.1, not TLS 1.0.
- *out = TLS1_1_VERSION;
- return true;
-
- case DTLS1_2_VERSION:
- *out = TLS1_2_VERSION;
- return true;
-
- default:
- return false;
- }
- }
-
- // The follow arrays are the supported versions for TLS and DTLS, in order of
- // decreasing preference.
-
- static const uint16_t kTLSVersions[] = {
- TLS1_3_DRAFT28_VERSION,
- TLS1_3_DRAFT23_VERSION,
- TLS1_2_VERSION,
- TLS1_1_VERSION,
- TLS1_VERSION,
- };
-
- static const uint16_t kDTLSVersions[] = {
- DTLS1_2_VERSION,
- DTLS1_VERSION,
- };
-
- static void get_method_versions(const SSL_PROTOCOL_METHOD *method,
- const uint16_t **out, size_t *out_num) {
- if (method->is_dtls) {
- *out = kDTLSVersions;
- *out_num = OPENSSL_ARRAY_SIZE(kDTLSVersions);
- } else {
- *out = kTLSVersions;
- *out_num = OPENSSL_ARRAY_SIZE(kTLSVersions);
- }
- }
-
- bool ssl_method_supports_version(const SSL_PROTOCOL_METHOD *method,
- uint16_t version) {
- const uint16_t *versions;
- size_t num_versions;
- get_method_versions(method, &versions, &num_versions);
- for (size_t i = 0; i < num_versions; i++) {
- if (versions[i] == version) {
- return true;
- }
- }
- return false;
- }
-
- // The following functions map between API versions and wire versions. The
- // public API works on wire versions, except that TLS 1.3 draft versions all
- // appear as TLS 1.3. This will get collapsed back down when TLS 1.3 is
- // finalized.
-
- static const char *ssl_version_to_string(uint16_t version) {
- switch (version) {
- case TLS1_3_DRAFT23_VERSION:
- case TLS1_3_DRAFT28_VERSION:
- return "TLSv1.3";
-
- case TLS1_2_VERSION:
- return "TLSv1.2";
-
- case TLS1_1_VERSION:
- return "TLSv1.1";
-
- case TLS1_VERSION:
- return "TLSv1";
-
- case DTLS1_VERSION:
- return "DTLSv1";
-
- case DTLS1_2_VERSION:
- return "DTLSv1.2";
-
- default:
- return "unknown";
- }
- }
-
- static uint16_t wire_version_to_api(uint16_t version) {
- switch (version) {
- // Report TLS 1.3 draft versions as TLS 1.3 in the public API.
- case TLS1_3_DRAFT23_VERSION:
- case TLS1_3_DRAFT28_VERSION:
- return TLS1_3_VERSION;
- default:
- return version;
- }
- }
-
- // api_version_to_wire maps |version| to some representative wire version. In
- // particular, it picks an arbitrary TLS 1.3 representative. This should only be
- // used in context where that does not matter.
- static bool api_version_to_wire(uint16_t *out, uint16_t version) {
- if (version == TLS1_3_DRAFT23_VERSION ||
- version == TLS1_3_DRAFT28_VERSION) {
- return false;
- }
- if (version == TLS1_3_VERSION) {
- version = TLS1_3_DRAFT23_VERSION;
- }
-
- // Check it is a real protocol version.
- uint16_t unused;
- if (!ssl_protocol_version_from_wire(&unused, version)) {
- return false;
- }
-
- *out = version;
- return true;
- }
-
- static bool set_version_bound(const SSL_PROTOCOL_METHOD *method, uint16_t *out,
- uint16_t version) {
- if (!api_version_to_wire(&version, version) ||
- !ssl_method_supports_version(method, version) ||
- !ssl_protocol_version_from_wire(out, version)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_SSL_VERSION);
- return false;
- }
-
- return true;
- }
-
- static bool set_min_version(const SSL_PROTOCOL_METHOD *method, uint16_t *out,
- uint16_t version) {
- // Zero is interpreted as the default minimum version.
- if (version == 0) {
- // TLS 1.0 does not exist in DTLS.
- *out = method->is_dtls ? TLS1_1_VERSION : TLS1_VERSION;
- return true;
- }
-
- return set_version_bound(method, out, version);
- }
-
- static bool set_max_version(const SSL_PROTOCOL_METHOD *method, uint16_t *out,
- uint16_t version) {
- // Zero is interpreted as the default maximum version.
- if (version == 0) {
- *out = TLS1_2_VERSION;
- return true;
- }
-
- return set_version_bound(method, out, version);
- }
-
- const struct {
- uint16_t version;
- uint32_t flag;
- } kProtocolVersions[] = {
- {TLS1_VERSION, SSL_OP_NO_TLSv1},
- {TLS1_1_VERSION, SSL_OP_NO_TLSv1_1},
- {TLS1_2_VERSION, SSL_OP_NO_TLSv1_2},
- {TLS1_3_VERSION, SSL_OP_NO_TLSv1_3},
- };
-
- bool ssl_get_version_range(const SSL_HANDSHAKE *hs, uint16_t *out_min_version,
- uint16_t *out_max_version) {
- // For historical reasons, |SSL_OP_NO_DTLSv1| aliases |SSL_OP_NO_TLSv1|, but
- // DTLS 1.0 should be mapped to TLS 1.1.
- uint32_t options = hs->ssl->options;
- if (SSL_is_dtls(hs->ssl)) {
- options &= ~SSL_OP_NO_TLSv1_1;
- if (options & SSL_OP_NO_DTLSv1) {
- options |= SSL_OP_NO_TLSv1_1;
- }
- }
-
- uint16_t min_version = hs->config->conf_min_version;
- uint16_t max_version = hs->config->conf_max_version;
-
- // OpenSSL's API for controlling versions entails blacklisting individual
- // protocols. This has two problems. First, on the client, the protocol can
- // only express a contiguous range of versions. Second, a library consumer
- // trying to set a maximum version cannot disable protocol versions that get
- // added in a future version of the library.
- //
- // To account for both of these, OpenSSL interprets the client-side bitmask
- // as a min/max range by picking the lowest contiguous non-empty range of
- // enabled protocols. Note that this means it is impossible to set a maximum
- // version of the higest supported TLS version in a future-proof way.
- bool any_enabled = false;
- for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kProtocolVersions); i++) {
- // Only look at the versions already enabled.
- if (min_version > kProtocolVersions[i].version) {
- continue;
- }
- if (max_version < kProtocolVersions[i].version) {
- break;
- }
-
- if (!(options & kProtocolVersions[i].flag)) {
- // The minimum version is the first enabled version.
- if (!any_enabled) {
- any_enabled = true;
- min_version = kProtocolVersions[i].version;
- }
- continue;
- }
-
- // If there is a disabled version after the first enabled one, all versions
- // after it are implicitly disabled.
- if (any_enabled) {
- max_version = kProtocolVersions[i-1].version;
- break;
- }
- }
-
- if (!any_enabled) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SUPPORTED_VERSIONS_ENABLED);
- return false;
- }
-
- *out_min_version = min_version;
- *out_max_version = max_version;
- return true;
- }
-
- static uint16_t ssl_version(const SSL *ssl) {
- // In early data, we report the predicted version.
- if (SSL_in_early_data(ssl) && !ssl->server) {
- return ssl->s3->hs->early_session->ssl_version;
- }
- return ssl->version;
- }
-
- uint16_t ssl_protocol_version(const SSL *ssl) {
- assert(ssl->s3->have_version);
- uint16_t version;
- if (!ssl_protocol_version_from_wire(&version, ssl->version)) {
- // |ssl->version| will always be set to a valid version.
- assert(0);
- return 0;
- }
-
- return version;
- }
-
- bool ssl_supports_version(SSL_HANDSHAKE *hs, uint16_t version) {
- SSL *const ssl = hs->ssl;
- uint16_t protocol_version;
- if (!ssl_method_supports_version(ssl->method, version) ||
- !ssl_protocol_version_from_wire(&protocol_version, version) ||
- hs->min_version > protocol_version ||
- protocol_version > hs->max_version) {
- return false;
- }
-
- // If the TLS 1.3 variant is set to |tls13_default|, all variants are enabled,
- // otherwise only the matching version is enabled.
- if (protocol_version == TLS1_3_VERSION) {
- switch (ssl->tls13_variant) {
- case tls13_draft23:
- return version == TLS1_3_DRAFT23_VERSION;
- case tls13_draft28:
- return version == TLS1_3_DRAFT28_VERSION;
- case tls13_default:
- return true;
- }
- }
-
- return true;
- }
-
- bool ssl_add_supported_versions(SSL_HANDSHAKE *hs, CBB *cbb) {
- const uint16_t *versions;
- size_t num_versions;
- get_method_versions(hs->ssl->method, &versions, &num_versions);
- for (size_t i = 0; i < num_versions; i++) {
- if (ssl_supports_version(hs, versions[i]) &&
- !CBB_add_u16(cbb, versions[i])) {
- return false;
- }
- }
- return true;
- }
-
- bool ssl_negotiate_version(SSL_HANDSHAKE *hs, uint8_t *out_alert,
- uint16_t *out_version, const CBS *peer_versions) {
- const uint16_t *versions;
- size_t num_versions;
- get_method_versions(hs->ssl->method, &versions, &num_versions);
- for (size_t i = 0; i < num_versions; i++) {
- if (!ssl_supports_version(hs, versions[i])) {
- continue;
- }
-
- CBS copy = *peer_versions;
- while (CBS_len(©) != 0) {
- uint16_t version;
- if (!CBS_get_u16(©, &version)) {
- OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
- *out_alert = SSL_AD_DECODE_ERROR;
- return false;
- }
-
- if (version == versions[i]) {
- *out_version = version;
- return true;
- }
- }
- }
-
- OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_PROTOCOL);
- *out_alert = SSL_AD_PROTOCOL_VERSION;
- return false;
- }
-
- bool ssl_is_draft28(uint16_t version) {
- return version == TLS1_3_DRAFT28_VERSION;
- }
-
- } // namespace bssl
-
- using namespace bssl;
-
- int SSL_CTX_set_min_proto_version(SSL_CTX *ctx, uint16_t version) {
- return set_min_version(ctx->method, &ctx->conf_min_version, version);
- }
-
- int SSL_CTX_set_max_proto_version(SSL_CTX *ctx, uint16_t version) {
- return set_max_version(ctx->method, &ctx->conf_max_version, version);
- }
-
- int SSL_set_min_proto_version(SSL *ssl, uint16_t version) {
- if (!ssl->config) {
- return 0;
- }
- return set_min_version(ssl->method, &ssl->config->conf_min_version, version);
- }
-
- int SSL_set_max_proto_version(SSL *ssl, uint16_t version) {
- if (!ssl->config) {
- return 0;
- }
- return set_max_version(ssl->method, &ssl->config->conf_max_version, version);
- }
-
- int SSL_version(const SSL *ssl) {
- return wire_version_to_api(ssl_version(ssl));
- }
-
- const char *SSL_get_version(const SSL *ssl) {
- return ssl_version_to_string(ssl_version(ssl));
- }
-
- const char *SSL_SESSION_get_version(const SSL_SESSION *session) {
- return ssl_version_to_string(session->ssl_version);
- }
-
- uint16_t SSL_SESSION_get_protocol_version(const SSL_SESSION *session) {
- return wire_version_to_api(session->ssl_version);
- }
-
- int SSL_SESSION_set_protocol_version(SSL_SESSION *session, uint16_t version) {
- // This picks a representative TLS 1.3 version, but this API should only be
- // used on unit test sessions anyway.
- return api_version_to_wire(&session->ssl_version, version);
- }
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